Add new ascsers_cluster gatherer (#329)

* Add new ascsers_cluster gatherer

* Add resource_group and resource_name to ascsers_cluster gatherer

* Name test file properly

* Improve some error handling to avoid panics

---------

Co-authored-by: Eike Waldt <[email protected]>

internal/factsengine/gatherers/ascsers_cluster.go

@@ -0,0 +1,255 @@
+package gatherers
+
+import (
+	"context"
+	"encoding/json"
+	"encoding/xml"
+	"fmt"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/trento-project/agent/internal/core/cluster/cib"
+	"github.com/trento-project/agent/internal/core/sapsystem/sapcontrolapi"
+	"github.com/trento-project/agent/internal/factsengine/factscache"
+	"github.com/trento-project/agent/pkg/factsengine/entities"
+	"github.com/trento-project/agent/pkg/utils"
+)
+
+const (
+	AscsErsClusterGathererName = "ascsers_cluster"
+	Ensa1                      = "ensa1"
+	Ensa2                      = "ensa2"
+	EnsaUnknown                = "unknown"
+)
+
+// nolint:gochecknoglobals
+var (
+	AscsErsClusterDecodingError = entities.FactGatheringError{
+		Type:    "ascsers-cluster-decoding-error",
+		Message: "error decoding cibadmin output",
+	}
+
+	AscsErsClusterCibError = entities.FactGatheringError{
+		Type:    "ascsers-cluster-cib-error",
+		Message: "error parsing cibadmin output",
+	}
+)
+
+type AscsErsSidEntry struct {
+	EnsaVersion string               `json:"ensa_version"`
+	Instances   []AscsErsSidInstance `json:"instances"`
+}
+
+type AscsErsSidInstance struct {
+	ResourceGroup    string `json:"resource_group"`
+	ResourceInstance string `json:"resource_instance"`
+	Name             string `json:"name"`
+	InstanceNumber   string `json:"instance_number"`
+	VirtualHostname  string `json:"virtual_hostname"`
+	FilesystemBased  bool   `json:"filesystem_based"`
+	Local            bool   `json:"local"`
+}
+
+type AscsErsClusterGatherer struct {
+	executor   utils.CommandExecutor
+	webService sapcontrolapi.WebServiceConnector
+	cache      *factscache.FactsCache
+}
+
+func NewDefaultAscsErsClusterGatherer() *AscsErsClusterGatherer {
+	webService := sapcontrolapi.WebServiceUnix{}
+	return NewAscsErsClusterGatherer(utils.Executor{}, webService, nil)
+}
+
+func NewAscsErsClusterGatherer(executor utils.CommandExecutor, webService sapcontrolapi.WebServiceConnector,
+	cache *factscache.FactsCache) *AscsErsClusterGatherer {
+	return &AscsErsClusterGatherer{
+		executor:   executor,
+		webService: webService,
+		cache:      cache,
+	}
+}
+
+func (g *AscsErsClusterGatherer) SetCache(cache *factscache.FactsCache) {
+	g.cache = cache
+}
+
+func (g *AscsErsClusterGatherer) Gather(factsRequests []entities.FactRequest) ([]entities.Fact, error) {
+	log.Infof("Starting %s facts gathering process", AscsErsClusterGathererName)
+	var cibdata cib.Root
+
+	ctx := context.Background()
+
+	content, err := factscache.GetOrUpdate(
+		g.cache,
+		CibAdminGathererCache,
+		memoizeCibAdmin,
+		g.executor,
+	)
+
+	if err != nil {
+		return nil, CibAdminCommandError.Wrap(err.Error())
+	}
+
+	cibadmin, ok := content.([]byte)
+	if !ok {
+		return nil, AscsErsClusterDecodingError.Wrap("error casting the command output")
+	}
+
+	err = xml.Unmarshal(cibadmin, &cibdata)
+	if err != nil {
+		return nil, err
+	}
+
+	entries, err := getMultiSidEntries(ctx, g.cache, cibdata, g.webService)
+	if err != nil {
+		return nil, AscsErsClusterCibError.Wrap(err.Error())
+	}
+
+	factValues, err := mapMultiSidEntriesToFactValue(entries)
+	if err != nil {
+		return nil, AscsErsClusterDecodingError.Wrap(err.Error())
+	}
+
+	facts := []entities.Fact{}
+
+	for _, requestedFact := range factsRequests {
+		facts = append(facts, entities.NewFactGatheredWithRequest(requestedFact, factValues))
+	}
+
+	log.Infof("Requested %s facts gathered", AscsErsClusterGathererName)
+	return facts, nil
+}
+
+func getMultiSidEntries(
+	ctx context.Context,
+	cache *factscache.FactsCache,
+	cibdata cib.Root,
+	webService sapcontrolapi.WebServiceConnector,
+) (map[string]AscsErsSidEntry, error) {
+
+	result := make(map[string]AscsErsSidEntry)
+
+	for _, group := range cibdata.Configuration.Resources.Groups {
+		var instanceGroupFound, filesystemBased bool
+		var resourceGroup, resourceInstance, sid, instanceName, instanceNumber, virtualHostname string
+
+		for _, primitive := range group.Primitives {
+			for _, instanceAttribute := range primitive.InstanceAttributes {
+				if instanceAttribute.Name == "InstanceName" {
+					values := strings.Split(instanceAttribute.Value, "_")
+					if len(values) != 3 {
+						return nil, fmt.Errorf("incorrect InstanceName property value: %s", instanceAttribute.Value)
+					}
+
+					instanceGroupFound = true
+					resourceGroup = group.ID
+					resourceInstance = primitive.ID
+					sid = values[0]
+					instanceName = values[1]
+					virtualHostname = values[2]
+					if len(instanceName) < 2 {
+						return nil, fmt.Errorf("incorrect instance name within the InstanceName value: %s", instanceName)
+					}
+
+					instanceNumber = instanceName[len(instanceName)-2:]
+				}
+			}
+
+			if primitive.Type == "Filesystem" {
+				filesystemBased = true
+			}
+		}
+
+		if !instanceGroupFound {
+			continue
+		}
+
+		ensaVersion, local := getEnsaVersionInfo(ctx, cache, webService, sid, instanceNumber)
+		instance := AscsErsSidInstance{
+			ResourceGroup:    resourceGroup,
+			ResourceInstance: resourceInstance,
+			Name:             instanceName,
+			InstanceNumber:   instanceNumber,
+			VirtualHostname:  virtualHostname,
+			FilesystemBased:  filesystemBased,
+			Local:            local,
+		}
+
+		entry, found := result[sid]
+
+		if !found {
+			entry = AscsErsSidEntry{
+				EnsaVersion: EnsaUnknown,
+				Instances:   []AscsErsSidInstance{instance},
+			}
+		} else {
+			entry.Instances = append(entry.Instances, instance)
+		}
+
+		if local {
+			entry.EnsaVersion = ensaVersion
+		}
+
+		result[sid] = entry
+	}
+
+	return result, nil
+}
+
+// getEnsaVersionInfo returns the ensa version and if the sap instance is running locally in this host
+func getEnsaVersionInfo(
+	ctx context.Context,
+	cache *factscache.FactsCache,
+	webService sapcontrolapi.WebServiceConnector,
+	sid string,
+	instanceNumber string,
+) (string, bool) {
+
+	cacheEntry := fmt.Sprintf("%s:%s:%s:%s", SapControlGathererCache, "GetProcessList", sid, instanceNumber)
+	output, err := factscache.GetOrUpdate(
+		cache,
+		cacheEntry,
+		memoizeSapcontrol,
+		ctx,
+		webService,
+		instanceNumber,
+		mapGetProcessList,
+	)
+	if err != nil {
+		log.Warnf("error requesting GetProcessList information: %s", err.Error())
+		return EnsaUnknown, false
+	}
+
+	processes, ok := output.([]*sapcontrolapi.OSProcess)
+	if !ok {
+		log.Warnf("error decoding GetProcessList information")
+		return EnsaUnknown, false
+	}
+
+	for _, process := range processes {
+		switch process.Name {
+		case "enserver", "enrepserver":
+			return Ensa1, true
+		case "enq_server", "enq_replicator":
+			return Ensa2, true
+		}
+	}
+
+	return EnsaUnknown, true
+}
+
+func mapMultiSidEntriesToFactValue(entries map[string]AscsErsSidEntry) (entities.FactValue, error) {
+	marshalled, err := json.Marshal(&entries)
+	if err != nil {
+		return nil, err
+	}
+
+	var unmarshalled map[string]interface{}
+	err = json.Unmarshal(marshalled, &unmarshalled)
+	if err != nil {
+		return nil, err
+	}
+
+	return entities.NewFactValue(unmarshalled)
+}